Our previous work has shown that isocyanates, isothiocyanates and carbodiimides that are not activated by an electron withdrawing group react with aza-norbornenes in benzene at reflux to give the zwitterionic intermediate that would then be poised to undergo a [3,3]-sigmatropic 1, 3-diaza Claisen rearrangement to afford ureas ,thioureas and guanidines respectively while, the heterocumulenes that are activated by an electron withdrawing group react at room temperature undergoing a more facile rearrangement. In studying the electronic effects that influence the 1,3-diaza Claisen rearrangements we have recently investigated the reactivity of the tertiary allylic amines towards the rearrangement. Interestingly, while triallylamine requires neat rearrangement conditions at 160º C with tosyl isocyanate to afford the urea, the tertiary allylic amine with an electron deficient alkene undergoes rearrangement with tosyl isocyanate at room temperature in 15 minutes to give the urea product. With additional examples of this transformation investigated, we have made a significant progress in optimizing the reaction conditions and understanding the electronic factors that influence the 1, 3-diaza Claisen rearrangements.